Fluidically controlled pneumatic to mechanical converters

ABSTRACT

A device for converting the output of a fluid amplifier into rotational mechanical energy. Teeth are arranged upon both ends of a short piston as well as both ends of its cylinder. An oscillatory motion is imparted to the piston by rapidly switching the output of a fluid amplifier from one end of the piston to the other. Upon oscillation, for engagement of the piston and cylinder teeth will cause the piston to rotate.

Waited @ites tet Uniried et al.

[45] May 29, 1973 FLUIDICALLY CONTROLLED PNEUMATIC TO MECHANICAL CONVERTERS inventors: Happy H. Unfried, Los Angeles; John F. Cogger, Northridge, both of Calif.

Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

Filed: Apr. 29, 1971 Appl. No.: 138,413

U.S. Cl. ..102/8l, 91/3, 74/800 ..F42c 5/00 Field of Search ..l02/81; 91/3; 74/800 [56] References Cited UNITED STATES PATENTS- 3,093,306 6/1965 Warren ..102/8l X 3,306,538 2/1967 3,554,058 5/1969 3,568,602 3/1971 3,578,011 5/1971 Primary ExaminerSamuel W. Engle Attorney-R. S. Sciascia and Thomas 0. Watson, Jr.

[57] ABSTRACT A device for converting the output of a fluid amplifier into rotational mechanical energy. Teeth are arranged upon both ends'of a short piston as well as both ends of its cylinder. An oscillatory motion is imparted to the piston by rapidly switching the output of a fluid amplifier from one end of the piston to the other. Upon oscillation, for engagement of the piston and cylinder teeth will cause the piston to rotate.

2 Claims, 6 Drawing Figures PATENTEb W 2 9 3 INVENTORS HAPPY H. U/VFR/ED JOHN F. 606657? ATTORNEY Pmmmmzsnm SHEET 2 OF 2 FIG: 4

FLUIDICALLY CONTROLLED PNEUMATIC TO MECHANICAL CONVERTERS STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION tions, there has been a need for a device which performs as above with the additional capability of operating at a constant speed, over a wide range of supply pressures. Such a device may be utilized as both a pneumatic to mechanical energy converter and as a time base.

SUMMARY OF THE INVENTION The present invention provides the necessary conversion through the use of a short piston (rotor) having teeth on both its faces. In additon, the piston cylinder also has teeth at both its ends to receive the piston teeth. By causing the piston to oscillate, within cylinder, the engagement of the piston and cylinder teeth causes the piston to rotate in incremental steps. A fluid amplifier, of known design, is used to impart the oscillatory motion to the piston.

In one embodiment, a diaphram is employed to alternately drive the rotor. The use of the diaphram not only eliminates the need for complex sliding seals within the converter but, it also reduces the effects of pressure changes, in the supply, on the frequency of operation.

OBJECTS OF THE INVENTION An object of the present invention is the provision of a pneumatic to mechanical converter.

Another object is to provide such converters whose output is in incremental steps.

A further object of the invention is the provision of a pneumatic to mechanical converter having the capability of operating over a wide range of supply pressures.

Still another object is to provide a device which will operate at a constant speed to serve as both a pneumatic to mechanical converter and as a time base.

Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a preferred embodiment of the invention.

FIG. 2 illustrates an operational detail of the present invention.

FIG. 3 shows another preferred embodiment of the invention.

FIG. 4 shows still another preferred embodiment of the invention.

FIGS. 5 and 6 are equivalent circuit representations of the embodiment of FIG. 3 FIG. 5 showing the initial load during switching and FIG. 6 showing the final load during switching.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1, which illustrates a preferred embodiment of the invention, shows a bistable fluid amplifier I 1 operatively connected through output legs 12 and 13 and feedback lines 14 and 15 to the converter of the present invention 16. The reference characters R, and R represent the input and feedback resistances in lines 12 15. The fluid amplifier 11 with the connecting lines I 12 15, vents 1'7 and supply inlet 18 is of the wall attachment type arranged as a bistable switch. This basic fluid amplifier is well known and described in the general literature.

The converter 16 comprises a housing 20 having an internal chamber 21. Positioned within the internal chamber 21 is a piston-like rotor 22 which spans the major dimension of the internal chamber 21. The rotor 22 is provided, on both its faces, with a set of teeth 24 which are located generally at the outer edge of each face. A third and fourth set of teeth 25 are provided on the cylinder wall adjacent the rotor teeth 24. I

The rotor 22 is free to oscillate within the internal chamber 21 between the point where one set of rotor teeth 24 is in engagement with one set of cylinder teeth 25 and the point where the other sets of teeth'24 and 25 are in engagement as at 26. The vents 27 prevent flow between the two sides of the rotor 22.

Referring now to FIG. 2, there is shown a tooth arrangement generally similar to that shown in FIG; 1. The two outer sets of teeth 25 correspond generally to the cylinder teeth 25, while the teeth 24 on the internal member 22 correspond generally to the rotor teeth 24. It can be seen that as the member 22 moves from the upper set of teeth to the lower set of teeth the nature of the engagement between the teeth 24' and 25' will cause the member 22' to move to the right. In the environment of FIG. I, a configuration of teeth such as that shown in FIG. 2, will cause the rotor 22 to rotate within the internal chamber 21. Thus, as the fluid amplifier 11 switches its output from one side of the rotor 22 to the other, the rotor 22 is caused to oscillate and this oscillation leads to a rotation of the rotor 22.

Referring now to FIG. 3, which shows another preferred embodiment of the inveniton, there is shown a fluid amplifier 11 connected to a converter 31. The fluid amplifier I1 is generally similar to that shown in FIG. I. Identical reference numerals have been used to designate functionally similar elements.

The converter 31, of FIG. 3, is comprised of a housing 32 containing a rotor 34 and an armature 35 within a first internal chamber 33. An armature extending portion 36 extends through a bore in the housing 32 from the first internal chamber 33 into a second internal chamber. A diaphragm 40 divides this second chamber into two compartments 38 and 39 and is connected to the armature extending portion 36.

Any suitable material may be used to make the diaphragm. It has been found that a polyester film such as 1 mil thick mylar is suitable for this purpose. Additionally, the diaphragm may be formed in a die to provide it with convolutions to enhance its flexural properties.

It will be noted that in the embodiment of FIG. 3, each side of the fluid amplifier 11 is connected to a different side of the diaphragm 40. This is analogous to the connection to the different sides of the rotor 22 in FIG. 1. As the output of the fluid amplifier 1 l switches between output legs 12 and 13, the action of the diaphragm causes the armature 35 to oscillate within the chamber 33. The armature 35 is provided with teeth 24 for engagement with teeth 25 on the rotor 34. This tooth arrangement is identical to that found on the rotor 22 and internal cylinder 21 of FIG. 1 and illustrated in FIG. 2. Thus, oscillation of the armature 35 and engagement of the teeth 24 and 25 (as shown at reference numeral 26) causes the rotor 34 to rotate. The minimum torque exerted on the rotor by the armature is given by the equation:

T R, (Sin 7 p. Cos-y)/(p. Sin 7 Cos 'y) .4 34 tk where R, rotor radius;

'y tooth angle;

a. coefficient friction armature to rotor teeth;

A diaphragm active area;

S pressure gradient across diaphragm;

t tooth depth; and

k diaphragm stiffness.

A major advantage in the use of the diaphragm 40, as shown in FIG. 3, is the elimination of an otherwise necessary sliding seal at the large diameter of the armature O.D. In the embodiment of FIG. 3, the only seal necessary is where the armature extending poriton 36 passes through the bore in the housing 32. By maintaining the clearance in the bore at about 2 to 3 mils a dynamic seal is formed since a flow path of this size has a high impedence to the approximately 100 cps signal that exists in the diaphragm compartment 39.

Referring briefly to FIGS. 5 and 6, there is shown the equivalent circuits for the case of the initial load and final load during a half cycle of operation of the device in FIG. 3. Reference characters shown in FIGS. 5 and 6 are shown on FIG. 3 adjacent there respective reference numerals. These figures are the equivalent circuit for the case of a solid armature. Note that in the final load case (FIG. 6) the capacitance C is missing. This capacitance C of the diaphragm, is what contributes to the frequency stability of circuit. Thus, through the use of the diaphragm 40, the converter 31 will operate at a more constant speed, over a wider range of supply pressures at the supply inlet 18, than would otherwise be possible.

FIG. 4, illustrates still another embodiment of the present invention. This embodiment employs a monostable fluid amplifier 1 1 connected to opposite sides of a rotor 43 through lines 12 and 13'. The primed reference numerals designate elements which are functionally similar to the elements containing identical unprimed reference numerals in FIGS. 1 and 3. The rotor 43 is keyed to the shaft 44 but is free to slide axially along it for oscillation. On the end of the shaft 44, opposite of the rotor 43, there is a disc 45. The stepping action of the rotor 43 induced by rotor oscillation causes the disc 45 to rotate due to the keyed connection between the rotor 43 and shaft 44.

An explosive primer 46 is mounted in a bore in the rim of the disc 45 and an explosive booster 47 is mounted outside the housing 48. A firing pin 49 is located within the housing 48. In the armed position, the firing pin 49, primer 46 and booster 47 are in alignment (as shown). In the unarmed mode, the primer 46 is held out of line with respect to both the firing pin 49 and booster 47. The monostable switch 11' and converter 40 are intended for use in a bomblet with the longitudinal axis of the bomblet being perpendicular to the axis of the rotor 43. The ram air, shown entering at 18' and 54, is derived from the falling of the bomblet.

The ram air entering at 18' powers the monostable switch 11' to turn the disc 45 until the primer 46, booster 47 and firing pin are in alignment (as shown). A limit pin (not shown) then stops the rotor and disc rotation. The device is now armed.

The ram air inlet 54 serves as a pressure source to push the firing pin 49 towards the center of the disc 45 and away from the primer 46. This permits the firing pin 49 to be loose so that it could and would assume a position at the rim of the disc when no ram air was present. If, in some manner the, disc 45 had been rotated to the armed position by faulty manufacture or failure, a bomblet containing this present invention could still not detonate unless ram air were present to provide sufficient space between the pin 49 and the primer 46. The space is needed to permit the pin acceleration to be achieved which could result in an enough energy to fire the primer 46.

The vent 55 allows leakage air around the shaft connecting the disc and rotor to escape to atmosphere and also allows the back side of the pin 49 to remain at atmospheric pressure when it is accelerated towards the primer 46. The vent 51, above the rotor 43, acts to prevent flow between the two sides of the rotor 43.

An alternative arrangement to stop the rotor 43 and disc 45 in the aligned position would be to provide the face of the rotor 43 with a depression in its face. This depression may be so located that when the rotor has stepped to its desired position it cannot block flow through the feed back port 53 to the control port of the monostable switch 11'. This would prevent the switch 11' from transferring flow to its right output port and the rotor 43 would thus cease to oscillate. The stopping point may be changed by making the feedback port 53 rotatable about the axis of the rotor 43.

From the above, it should be apparent that the device of applicant's invention may be used as a pulse counter or an accumulator by a person with ordinary skill in the art of fluidic digital techniques. In addition, by merely attaching a pointer or number wheel to the output shaft of the device, it may be operated as a readout device for fluidic pneumatic or hydraulic systems which have a pulse output.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is:

l. A pneumatic to mechanical converter which comprises:

a housing having an internal cylinder;

a first and second set of teeth within said internal cylinder;

an oscillating element, having two faces; rotatably positioned within said internal cylinder spanning its major dimension;

a third set of teeth located upon one face of said os-' cillating element and positioned to be engageable with said first set of teeth;

a fourth set of teeth located upon the other face of said oscillating element and positioned to be engageable with said second set of teeth, the crosssection of said four sets of teeth being such that an engagement alternating between the first and third set of teeth and the second and fourth set of teeth causes a relative motion, in the form of a stepping action, between the first and second set of teeth and the oscillating element;

an external means for causing said oscillating element to oscillate within said internal cylinder;

a disc connected to said oscillating element to rotate therewith; an explosive primer located on said disc at a point away from the center of the disc; 5 a firing pin within said housing; and

an explosive booster on said housing, said firing pin, primer and booster being located so as to be aligned in one angular position of said disc. 2. The pneumatic to mechanical converter of claim 10 1 wherein the power supply to the external means also acts upon the firing pin to position and maintain it in at the center of the disc away from the explosive primer. 

1. A pneumatic to mechanical converter which comprises: a housing having an internal cylinder; a first and second set of teeth within said internal cylinder; an oscillating element, having two faces, rotatably positioned within said internal cylinder spanning its major dimension; a third set of teeth located upon one face of said oscillating element and positioned to be engageable with said first set of teeth; a fourth set of teeth located upon the other face of said oscillating element and positioned to be engageable with said second set of teeth, the cross-section of said four sets of teeth being such that an engagement alternating between the first and third set of teeth and the second and fourth set of teeth causes a relative motion, in the form of a stepping action, between the first and second set of teeth and the oscillating element; an external means for causing said oscillating element to oscillate within said internal cylinder; a disc connected to said oscillating element to rotate therewith; an explosive primer located on said disc at a point away from the center of the disc; a firing pin within said housing; and an explosive booster on said housing, said firing pin, primer and booster being located so as to be aligned in one angular position of said disc.
 2. The pneumatic to mechanical converter of claim 1 wherein the power supply to the external means also acts upon the firing pin to position and maintain it in at the center of the disc away from the explosive primer. 